1. Field
The invention relates to a transceiver circuit for compensating an IQ mismatch and/or a carrier leakage.
2. Background
A technology for converting a base band signal (hereinafter referred to as ‘BB signal’) or an intermediate frequency signal (hereinafter referred to as ‘IF signal’) to a radio frequency signal (hereinafter referred to as ‘RF signal’) or converting the RF signal to the BB signal or IF signal using an IQ mixer is widely used in a wireless communication field.
However, a carrier leakage and an IQ mismatch occur in a real IQ mixer. The carrier leakage is a phenomenon that occurs when an IQ local oscillator (LO) signal leaks to an output of the IQ mixer as well as when a product of an input signal and the IQ LO signal transmitted from an local oscillator is transmitted to the output of the IQ mixer. The IQ mismatch includes a gain imbalance that occurs because of a difference in amplitudes of an in-phase signal and the quadrature signal transmitted to the IQ mixer from the oscillator and a phase imbalance that occurs because of a phase difference between the in-phase signal and the quadrature signal not being 90°. When the carrier leakage and the IQ mismatch occur, an undesirable noise component exists in the output of the IQ mixer to degrade a signal-to-noise ratio.
In accordance with related art technologies (e.g., U.S. Pat. Nos. 5,949,821; 6,044,112; Korean Patent Publication No. 10-2005-66953), a method for measuring an Rx IQ mismatch using a received signal transmitted through a wireless communication has been disclosed. However, in accordance with the method, the IQ mismatch is measured using the received signal. Therefore, the methods are disadvantageous in that an IQ mismatch of a signal that is received prior to a compensation of the IQ mismatch cannot be compensated or that an accuracy of the IQ mismatch measured is degraded by a noise of a wireless channel included in the received signal.
Other related art technology such as U.S. Publication No. 2005/0070236 discloses a method wherein a test signal is inputted to a down-conversion IQ mixer to measure the Rx IQ mismatch. However, the method disclosed by the publication is disadvantageous in that a separate test signal is required.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.